Harvesting of Useful Herbs in India!
1. Harvesting of Amaranthus:
In the North Indian hills, the grain crop is harvested from September onwards and in the South Indian hills during Aug-Sept. The tops of the mature grain plants are cut with sickles while they are still in somewhat green stage, collected in cloth sheets, spread on the threshing yard and trodden under the feet of bullocks and then winnowed. Grains are allowed to dry for two or three days.
Foliage amaranths are cut periodically, when the leaves are crisp and green. The first cutting is done after 3 or 4 weeks of sowing and subsequent cuttings may be done after 7-10 days. Depending upon the type, 8-10 cuttings are taken in all. In South India and West Bengal, the thickened stems of fully grown plants are also used. In types of A. hybridus ssp. hybridus harvesting after 6 weeks of sowing gives the highest yield.
For collecting the seeds from the leafy amaranths, the last one or two cuttings of leaves are not taken and the crop is harvested when most of the leaves turn yellow. After drying, the seeds are separated, winnowed, cleaned and collected.
Yield:
The average crop yields 900- 1,100kg of seeds per hectare. The yield of greens varies from 4,000 to 16,000 kg/ha, although the average yield is between 9,000 and 10,000 kg/ha. The type ‘Co 1’ yields, on an average, 18,700 kg of greens per hectare with 31-51% increase over the local types. The grain yield in leafy amaranths varies from 180 to 280 kg/ha according to the crop and its type.
2. Harvesting of Amorphophallus:
The crop matures in a period of seven to eight months after every planting. Yellowing and dropping of the leaves are the signs of maturity of the crop. The corms are lifted by digging them up individually with a spade after the surrounding soil is first softened and removed. They are cleaned of the roots and the adhering soil. The buds on the fourth-year corms are removed and preserved as a seed material for the first-year crop. The corms should be disposed of as early as possible as they lose moisture rapidly in the first four days.
If the prices are high, the corms can be harvested in the sixth month; and if the market is dull, it can be postponed to the tenth month. The corms can be retained in the soil even after maturity, but then a light irrigation after a long interval is required to prevent desiccation of the corms in the soil. The corms can be graded on the basis of uniformity of size and shape; large-size, uniform and hemispherical shape, and absence of deformities and protrusions are good market qualities.
Yield:
The yield of corms is reported to be 11,200, 17,920, 28,000 and 44,800 kg/ha after first, second, third and fourth year, respectively. Yields as high as 55,000 kg/ ha have been reported from several areas. The yield is associated with the number of leaves, girth of seed-tubers, and seed weight per hectare.
3. Harvesting of Atropa Belladonna:
Belladonna yields two crops of leaves during the first year of growth. In the second and subsequent years, it gives three or four leaf crops. The roots are, however, dug out after the third or fourth year of planting. Harvesting begins with the first sign of flowering when the alkaloid content in the plant is at its peak. The plants are cut in August, about 30 cm above the ground with a sickle or a cutter, while in the autumn, they are cut 3cm close to the ground.
Cutting at 30 cm height ensures quick regeneration of leaves and more leaf content and elimination of woody branches having low alkaloid content. The plants are irrigated and fertilized immediately after harvest so that, they put out new shoots again. The harvested crop is chopped into pieces, particularly the young herbaceous shoots, and dried by spreading in the sun in thin layers.
Losses up to 30 per cent can occur if the material is dried in thick layers. The material is periodically raked to ensure uniform drying to retain the green colour of leaves and also to prevent decomposition of alkaloids by enzymic action.
Drying at 40° for 24hrs ensures complete drying; hot air is sometimes employed for drying. The woody stems are discarded and the dried material is stored in gunny or polythene bags in well-ventilated sheds. Under humid conditions, the material absorbs moisture resulting in the lowering of alkaloid content. Lumps of calcium chloride kept in the store rooms help to avoid such moist conditions.
Yield:
The yield of leaves from a uniform belladonna crop varies between 500 and 600 kg/ha in the first year and reaches up to c 750 kg/ha in the subsequent years. At Seoni and Chaubattia (U.P.) yield up to 1,500 kg/ha is recorded in experimental trials. Grown as a winter annual in the plains of Jammu, the crop yields 1,440kg of leaves (dry wt.) and 240 kg of roots (dry wt.) per hectare. The ratio of stem to leaf in the harvested leaf crop is 50:50 by weight.
In temperate climate, the roots are dug out by ploughing after the third or fourth year of planting. They are washed and cleaned and cut into short pieces of c 10cm; the thicker ones are sliced lengthwise. They are dried thoroughly in the sun or by artificial heat. The yield of roots is c 160 kg/ha.
The drug (belladonna) consists of cylindrical pieces of the roots upto 3 cm thick, occasionally branched, slightly contorted and with a short tough fracture. They are pale brownish grey, and longitudinally wrinkled. Pieces with the crown are 3-9 cm in diameter at the top and have bases of 4-12 aerial stems. The powdered root is grey to light brown in colour. It has a characteristic odour and a sweetish taste which later becomes bitter.
The drug from the leaves, called belladonna herb, has a slight odour and a somewhat bitter and acrid taste. It consists of the dried leaves; the powdered leaves are greenish yellow. Sometimes, flowers with short pedicels, immature fruits and seeds are found in the drug.
4. Harvesting of Carum Carui:
The crop flowers in the first week of June and matures during the middle of July in the hills. It is harvested when the seeds turn brown; for seed purposes, it is allowed to mature completely. Harvesting is done preferably in the early morning to prevent loss of seeds due to shattering of fruits. The plants are cut and dried, and threshing is done by beating the fruits with sticks. The yield of seed is 600-750 kg/ha but yields up to 900 kg/ha have been recorded in experiments in Chakrata.
The separated mericarps (commonly called seeds) constitute the commercial caraway. It has a characteristic agreeable odour and an aromatic, somewhat warm and sharp taste. It is marketed either whole or ground. It is considered superior in taste and fragrance to cumin. The ground product is sometimes adulterated with cheaper seeds of similar flavour, farinaceous products, or other vegetable seeds.
The fruits of Bunium persicum (Boiss.) Fedts., B. cylindricum (Boiss. & Hoh.) Drude, Cuminum cyminum Linn, and Bupleurum lanceolatum Wall, ex DC. are offered in commerce as caraway and are often substituted or used as adulterants. Other adulterants are Carum villosum Haines, Anethum sowa Kurz, A. graveolens Linn., Foeniculum vulgare Mill. var. vulgare and var. dulce (Mill.) Thell.
The stored seeds are sometimes found infested with several fungi such as Aspergillus fumigatus Fres., A. niger van Tiegh., A. flavus Link, A. terreus Thom, A. sydowi (Bain. & Sart.) Thorn & Church, Acremonium vitis, Rhizopus nigricans Ehrenb., Fusarium moniliforme Sheld., etc. These fungi deteriorate the quality of the seeds and render them unsuitable for consumption due to production of certain toxic substances. It was observed that leaf extracts of Nephrolepis volubilis (J. Smith) Clarke syn. N. exaltata Schott and Pteris longifolia Linn, inhibited the spore germination of these fungi.
Caraway seeds are widely used as a spice for culinary purposes and for flavouring bread, biscuits, cakes, candies, cheese, curries, pickles, sausages, meat products, confectionery and liqueurs of kummel type. They are also used as a flavouring constituent in cordials and in certain preparations of Cannabis. In medicine, they are used as a carminative, mild stomachic, aromatic and diuretic. Both the seeds and the essential oil (caraway oil) are classed as carminative in the I.P. and prescribed in flatulent colic and stomach derangements.
In patients suffering from lumbago and rheumatism, exposing the affected parts to the vapours from the seeds gives relief from the disease. The alcoholic extract of the fruits shows dose-dependent anti-spasmodic effect. Caraway water finds use as a vehicle for paediatric medicines. Hexane extract of the fruits was found to have excellent larvicidal activity against the mosquito Culex pipiens fatigans Wiedm.
5. Harvesting of Chrysanthemum Cinerari Folium:
The synthesis of pyrethrins closely follows the maturity of flowers. For optimum benefits, harvesting can be started much early in the season when the flowers are immature with ray florets horizontal but are best harvested at the stage when three-fourths of disc florets are open; delay in picking affects pyrethrin content. The immature flower heads not only reduce yield of pyrethrins, but increase carotenoid content of oleoresin. At Kodaikanal, it was observed that the yield and quality of flower improve if picked at an interval of 7-14 days.
Harvesting should be avoided during the rains or in the early hours, as the moisture present in the flowers proves harmful during drying. After harvesting, the plants may be left as such, or should be cut at 15-20 cm above the ground for initiating fresh growth in the next season. The production of flower is greatly influenced by weeds. Hence, the pre-emergence spray of TOK-E 25 at 4.0 1/ha along with hand-weeding at 45 days after chemical spray is beneficial for higher yield.
The picked flowers are dried partly under the sun and partly under shade by spreading in two layers. Shade-drying is preferred. The fresh flowers should not be heaped where they would ferment, but should be spread thinly on the wire trays at density of 3.66 kg/ m2. Mechanical dryers may also be used. The harvested flowers are spread on trays and dried in specially constructed driers in which there is an upward natural draught of hot air heated by passing over hot flues.
The process takes 6-8 hrs during which, moisture content is reduced from 75-83 per cent to 8-10 per cent. Drying under controlled conditions does not reduce pyrethrin content appreciably, although pyrethrum powder and dust exposed in thin layers to air and sunlight rapidly lose activity due to oxidation.
The flowers are packed in gunny bags and forwarded for further processing. Pyrethrum flowers, both whole and ground, lose their activity on storage regardless of the type of containers used for storage. After 20 months storage about 45 per cent of insecticidal activity is lost in dried flowers and somewhat less in the powder. Anti-oxidants apparently retard decomposition to some extent. The flowers, therefore, should be processed without delay.
Yield:
The yield of flowers varies, depending upon the altitude, soil and management. At Kodaikanal, it is observed that for a rise of 360m height (over 1,800 m elevation) the pyrethrin content increased by 0.15 per cent in flowers. The yield of dry flowers at Srinagar varies from 4 to 5 qt/ha and that at Kodaikanal from 2.5 to 3.0 qt/ ha. In a varietal trial at Kodaikanal, strain ‘No.387’ yielded about 6 qt/ha of dried flowers.
However, higher yield is possible in Kashmir through some cultivars which flower a second and third time in the growing season. The yield was more at Kodaikanal during the second year, reaching the peak during the third and fourth year. If well- maintained, the plantation is productive for 4-5 years.
6. Harvesting of Dhattura:
All parts of the Thorn-apple have medicinal value, but only the leaves and seeds are official. The United States Pharmacopoeia formerly recognized leaves, root and seeds, but since 1900 the leaves alone are recognized as official. They are used in the dried state and are referred to as Stramonium.
Stramonium leaves are official in all Pharmacopoeias. Many require that they be renewed annually. The Belgian excludes discoloured leaves. The Portuguese directs the use of the entire plant except the root, and allows the substitution of D. Tatula. To how great an extent it is true that the quality deteriorates on being kept is conjectural.
The commercial drug as imported into Great Britain consists of the leaves and young shoots, collected while the plant is in flower, and subsequently dried, and containing the shrivelled, bristly young fruits, tubular calyx, and yellowish corolla, but the official description, for medicinal purposes, permits the use of the leaves only.
The leaves should be gathered when the plant is in full bloom and carefully dried. The United States Pharmacopoeia considers that they may be gathered at any time from the appearance of the flowers till the autumnal frosts. In this country, they are generally harvested in late summer, about August, the crop being cut by the sickle on a fine day in the morning, after the sun has dried off the dew, and the leaves stripped from the stem and dried carefully as quickly as possible, as for Henbane.
The dried leaves are usually much shrivelled and wrinkled, and appear in commerce either loose, or more or less matted together, of a dark-greyish green colour, especially on the upper surface, stalked and often unequal at the base, and are characterized by the very coarse pointed teeth. About 34 parts of dried leaves are produced from 100 parts of fresh leaves.
The fresh leaves, when bruised, emit a foetid, narcotic odour which they lose on drying. Their taste is bitter and nauseous. These properties, together with their medicinal values, are imparted to water and alcohol and the fixed oils. The leaves if carefully dried, retain their bitter taste.
The inspissated juice of the fresh leaves was formerly commonly prescribed, but the alcoholic extract is now almost exclusively used.
Stramonium seeds are official in a number of Pharmacopoeias. The thorny capsules are gathered from the plants when they are quite ripe, but still green. They should then be dried in the sun for a few days, when they will split open and the seeds can be readily shaken out. The seeds can then be dried, either in the sun or by artificial heat.
The dried ripe seeds are dark brown or dull black in colour, flattened, kidney-shaped in outline, wrinkled and marked with small depressions, and average about 1/6 inch in length. Though ill-smelling when fresh, when dry they have a scarcely perceptible odour till crushed, but a bitter, oily taste. They should not be stored in a damp place, or will mildew. Kiln-dried seeds are no use for cultivation.
The demand for the seed is very limited, but the dry leaves find a ready market. The south of Europe furnishes a quantity, but owing to careless collection and neglect of botanical characters, the South European product is often mixed with other leaves of no value, which are sometimes entirely substituted for it, especially species of Xanthium, which has spiny though smaller fruits.
Spanish Stramonium which contains no Stramonium at all has been offered in London and Liverpool. The imported commercial Stramonium leaves are also frequently found freely adulterated with those of Carthamus helenoides.
7. Harvesting of Hyoscyamus Niger:
Much of the efficacy of Henbane depends upon the time at which it is gathered. The leaves should be collected when the plant is in full flower. In the biennial plant, those of the second year are preferred to those of the first; the latter are less clammy and foetid, yield less extractive, and are medicinally considered less efficient.
Sometimes, however, the plant is destroyed by a severe winter in England, and then no leaves of the second year’s growth are obtainable, and it has been suggested that this is, perhaps, one of the causes of the great uncertainty of the medicine as found in commerce.
The leaves of the biennial variety are collected in June or the first week of July and those of the annual in August.
The leaves and flowering tops which constitute the ‘Second Biennial Henbane’ are collected either with or without the smaller branches to which they are attached and carefully dried, unless they are required for the preparation of the juice or green extract, when they should be sent to the distillery at once on cutting.
The herb when required in the fresh state should be cut the first week in June, because in the second week, the leaf-mining insect attacks the leaves, leaving only patches of white epidermis.